The rate of students switching from public schools to private schools because they received a scholarship and would not have switched without the subsidy ("switcher rate") is an integral factor for reliably estimating the net fiscal impact of private school choice programs. Switcher rates observed among students in control groups in random assignment studies can provide useful information for inferring switcher rates among program participants when conducting fiscal analyses. This paper identifies 27 estimates of switcher rates from eight lottery-based evaluations of six private school choice programs in the United States that report information about which types of school students enroll in after they apply to a choice program and do not win a lottery. Switcher rates for both full samples and subgroups of students range from 52 percent to 98 percent. Lower bound weighted average and median switcher rates from these studies are 84 percent. Upper bound weighted average and median switcher rates are 90 percent and 89 percent, respectively. Switcher rates are slightly higher for African American students participating in three privately funded school choice programs, where the average switcher rate for these students is 93 percent and the median is 94 percent. Switcher rates observed in these studies are remarkably stable across time and states, and they can provide useful information for inferring switcher rates in fiscal analyses.